The present application is based on Japanese Patent Application No. 2001-39708, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a circuit forming element adapted to intervene among a plurality of terminals and enabled to arbitrarily form a connection circuit between the terminals.
2. Related Art
Conventional circuit forming elements are, for example, elements each applied to a joint connector disclosed in JP-A-2-5288U. As illustrated in FIGS. 12A and 12B, these elements are constituted as relay terminals 1 and 1xe2x80x2, each of which comprises a metal piece 1a, a connecting piece 1b, and an elastic contact piece 1c. As illustrated in FIG. 13, terminal metal fittings 4 are electrically conducted to each other by inserting this relay terminal 1 into a cavity of a terminal accommodating chamber 3 of the joint connector 2.
However, the conventional relay terminal 1 is constituted as a single bus bar manufactured by bend-forming a metal plate. A plurality of such relay terminals 1 are used and respectively attached between corresponding ones of the terminal accommodating chambers 3 from the front face of the joint connector 2. Thus, the mountability of the circuit forming elements is poor. Moreover, because a plurality of such relay terminals 1 are individually attached thereto, the tractability thereof is degraded with increase in the number of components thereof.
The invention is accomplished in view of such problems of the conventional circuit forming elements. An object of the invention is to provide a circuit forming element of the integrated type that is easy to handle and enabled to easily constitute an arbitrary circuit.
According to the invention, there is provided a circuit forming element (hereunder referred to as a fist circuit forming element of the invention), comprising: a bus bar including a plurality of pairs of terminal contact pieces, each pair of which are brought into contact respectively with the terminals opposing with each other provided in the housings adjoining to each other in the stacking direction, a pair of connecting base portions one of which integrally connects proximal ends of the terminal contact pieces disposed at one side while the other connecting base portion integrally connects proximal ends of the terminal contact pieces disposed at the other side, and connecting pieces connecting the pair of connecting base portions; wherein the bus bar is integrally coupled to a bus bar fixing member provided with an insulating member.
In this case, the bus bar is adapted so that each of the paired terminal contact pieces is electrically conducted to the connecting base portion, and that the connecting base portions are electrically conducted to each other through the connecting piece. Therefore, in this state, a terminal contact piece, which is in contact with a specific terminal, is electrically conducted through one of connecting base portions, which is connected to this terminal contact piece, to another terminal contact piece connected to this connecting base portion and is also electrically conducted to another connecting base portion through a connecting piece. Moreover, the terminal contact piece, which is in contact with the specific terminal, is electrically conducted to a pair of terminal contact pieces through this connecting base portion. Consequently, all the terminal contact pieces are electrically conducted to one another. In this state, one or both of a pair of connecting base portions are cut at appropriate places, alternatively, the connecting piece is cut. Thus, an arbitrary circuit including so-called a skip connection can be configured. Further, the bus bar capable of constructing an arbitrary circuit in this way is coupled to the bus bar fixing member, so that the contact state between the bus bar and the terminal can be held without excessively increasing the strength of the bus bar. Thus, the entire circuit forming element is constructed as one component.
According to an embodiment (hereunder referred to as a second circuit forming element of the invention) of the first circuit forming element of the invention, the pair of connecting base portions are offset with respect to each other so that the two connecting base portions do not overlap each other in a plane of projection in a direction of opposing of the connecting base portions to each other.
In this case, when a pair of connecting base portions are cut at appropriate places and cutting blades are inserted from opposed directions thereof, both the connecting base portions are displaced from each other. Thus, the connecting base portions are easy to individually cut.
According to an embodiment (hereunder referred to as a third circuit forming element of the invention) of the first or second circuit forming element of the invention, proximal ends of the terminal contact pieces are integrally connected to the bus bar fixing member.
In this case, each of the terminal contact pieces is fixed to the bus bar fixing member at the proximal end thereof. Thus, the spring forces of the terminal contact pieces are effectively exerted, so that the contact force acting between the terminal contact piece and the terminal is ensured.
According to an embodiment (hereunder referred to as a fourth circuit forming element of the invention) of one of the first to third circuit forming elements of the invention, a coupling between the bus bar and the bus bar fixing member is fixed through an opening formed in the bus bar and a protrusion having a flange portion, which is formed on the bus bar fixing member and fitted into the opening by simultaneously forming a partial gap between the protrusion and an inner circumferential portion of the opening.
In this case, when the flange portion of the protrusion is deformed during the flange portion is fitted into the opening formed in the bus bar, the deformed part gets into the gap. Consequently, an amount cut by the inner circumferential portion of the opening away from the flange portion can be reduced.
According to an embodiment (hereunder referred to as a fifth circuit forming element of the invention) of one of the first to fourth circuit forming elements of the invention, cutting portions are selectively formed on the bus bar in the vicinity of portions where the connecting base portion and the connecting piece are connected together.
In this case, the cutting portions are concentrated by cutting a part provided in the vicinity of the connection portion among the connecting base portions and the connecting pieces so that the connecting base portions and the connecting pieces are selectively cut at the cutting portions. Thus, the management of the electrically conducting relation is facilitated. Moreover, the cutting blades (not shown) for cutting the connecting base portions and the connecting piece can be concentrated to thereby realize a compact circuit forming element.
According to an embodiment (hereunder referred to as a sixth circuit forming element of the invention) of one of the first to fifth circuit forming elements of the invention, a lance for engaging the terminal in a direction to prevent the withdrawal thereof is provided in the terminal accommodating portion for accommodating the terminal, and the bus bar-fixing member has a lance-return regulating portion pressing the lance in a withdrawal prevention direction.
In this case, the lance-return regulating portion pushes the lance in the withdrawal preventing direction by attaching the circuit forming element. This enables the prevention of the return of the lance, that is, the cancellation of the state, in which the lance engages with the terminal.
According to an embodiment (hereunder referred to as a seventh circuit forming element of the invention) of one of the first to sixth circuit forming elements of the invention, a chamfered portion is formed at an opposite side edge of the terminal contact piece brought into contact with the terminal.
In this case, when the terminal contact piece is brought into contact with the terminal with a predetermined pushing force, the terminal can be prevented from being damaged by the side part of the contact portion of the terminal contact piece.
According to an embodiment (hereunder referred to as an eighth circuit forming element of the invention) of one of the first to seventh circuit forming elements of the invention, a U-shaped bending portion to be folded back on a side edge of the bus bar fixing member is provided in each of the connecting pieces, and wherein the U-shaped bending portions are outwardly exposed.
In this case, the U-shaped bending portion of the connecting piece is outwardly exposed. Thus, a measuring terminal of a tester can easily be brought into contact with this exposed part. Consequently, the conducting relation of the bus bar can be easily and reliably checked.